Coronavirus: WHO says mortality rate has surpassed influenza’s

NEW DELHI: Debunking the idea that influenza kills more people, the World Health Organisation (WHO) has said that the mortality rate of coronavirus (COVID-19) has surpassed influenza’s.

The WHO in its latest situation report has said that the reproductive number – the number of secondary infections generated from one infected individual – is understood to be between 2 and 2.5 for COVID-19 virus, higher than for influenza.

For seasonal influenza, mortality is usually well below 0.1%. However, mortality is to a large extent determined by access to and quality of health care.

“COVID-19 causes more severe diseases than seasonal influenza. While many people globally have built up immunity to seasonal flu strains, COVID-19 is a new virus to which no one has immunity. That means more people are susceptible to infection and some will suffer severe disease. Globally about 3.4% of reported COVID-19 cases have died. By comparison, seasonal flu generally kills far fewer than 1% of those infected,” said Tedros Adhanom Ghebreyesus, Director-General, WHO.

According to the WHO data, for COVID-19, data to date suggest that 80% of infections are mild or asymptomatic, 15% are severe infection, requiring oxygen and 5% are critical infections, requiring ventilation.

Scientists have said that the speed of transmission is an important point of difference between the two viruses. Influenza has a shorter median incubation period (the time from infection to appearance of symptoms) and a shorter serial interval (the time between successive cases) than the COVID-19 virus.

Scientists have been wondering if the number of cases will decrease with an increase in temperature, though nothing concrete has come to the fore.

“At the moment we do not know. This virus has been around for 10-12 weeks and it has not seen the summer months, and no studies have been done. Studies done earlier with other corona viruses have shown that beyond 30 degrees C, duration of persistence of the virus is shorter. How will this virus behave, we do not know,” said Lalit Kant, former head, Division of Epidemiology & Communicable Diseases, Indian Council of Medical Research (ICMR).

“COVID-19 is transmitted quite efficiently. The average infected person spreads the disease to two or three others. So the total number of infected individuals would be much more. Through mutations its virulence decreases and it stays with us like the H3N2(1968) or the H1N1 (2009) influenza virus. New cases would drive the cases up thus worsening the situation,” he said.